回答下列有关生物进化与生物多样性的问题：

随着生命科学技术的不断发展，物种形成、生物多样性发展机制的理论探索也在不断的发展与完善。下图是科学家利用果蝇所做的进化实验，两组实验仅喂养食物不同，其他环境条件一致。

对于任意x，x表示不超过x的最大整数，如1.1=1，﹣2.1=﹣3．定义R上的函数f（x）=2x+4x+8x，若A={y|y=f（x），0≤x≤1}，则A中所有元素的和为____ ．

    Today is the last Saturday before Christmas. Everyone in the USA 1 shopping for presents. 2 is falling. People are walking fast. They are trying to keep3 when they move from shop to shop. In the shops children are 4 at the toys. They are talking to a man called Father Christmas. He asks, "What do you want for Christmas?"

    In the USA it is warm and beautiful in summer. The trees and fields are green then. But now it is winter and 5is white.

    At 6, small lights make the houses and buildings 7. Christmas is a beautiful 8 of a year.

    Christmas Day always begins before 9. Children wake up very early in the morning. They open the 10from their parents. Then they wake up their parents, saying "Merry Christmas."

列举《共产党宣言》的主要内容和历史意义。

人的思维能力是自己唯一能完全控制的东西，没有正确的思维，就不会有正确的行动。那些成大事者都养成了勤于独立思考的习惯，善于发现问题、解决问题，不让问题成为人生的难题。从某种意义上讲，思维可以支撑起人生。